ET 710 then OS 336 at Heathrow
Addis Ababa → London → Vienna
Timetable, London time
14:25ET 710 from Addis Ababa at the gate
13:55OS 336 to Vienna leaves the gate
23 h 30 apart on the timetable, overnight
OS 336 leaves 23 h 30 after ET 710 arrives on the timetable: more than half a day, so not a connection we count.